Prevalence of Tracheostomy and Its Indications in Iran: A Systematic Review and Meta-Analysis

Background: Tracheostomy is common among intensive care unit (ICU) patients. Reconsideration of tracheostomy indications in patients can be effective in modifying and reducing irrevocable patient complaints. The present study aimed to analyze the prevalence of tracheostomy indications and to estimate the prevalence of tracheostomy in Iran. Materials and Methods: In this systematic review and meta-analysis, scientific databases were searched from January 1990 to April 2018. The inclusion criteria were as follows: 1) use of the term “tracheotomy” in the title; and 2) studies conducted in Iran. On the other hand, the exclusion criteria were: 1) studies that did not specify the type of mechanical ventilation; 2) studies that did not quantitatively report the indications; 3) studies without access to the full-text; and 4) case studies, letters to the editor, and/or prefaces. Data were extracted from published reports. Our preliminary results included estimations of tracheostomy indications in Iran. Results: In the preliminary search, a total of 325 articles were found, 24 of which were considered eligible. Among 2860 patients who had undergone tracheostomy, 21 indications were identified. Decreased mental status, respiratory disease, and tumors were the most frequent indications. The prevalence of tracheostomy was 40.59% in Iran, with the highest and lowest rates reported in Birjand and Ardabil, respectively (136.50 and 6.63 in 100,000 people, respectively) based on the random effects model. Conclusion: The most prevalent indications in Iran are different from those reported in other countries. This difference may be due to the lack of trained medical personnel and available technologies.


INTRODUCTION
Tracheostomy is the formation of a valve or opening into the trachea with the aim of facilitating air passage in upper airway obstructions and improving the discharge of pulmonary secretions or laryngeal storage in patients with long-term intubation (1,2). The site of incision is usually between the second and third tracheal rings (3). The history of this surgery dates back to pre-Christianity in Greece (1,4). According to previous studies, the prevalence of tracheostomy ranges from 6% to 65% (3). In this regard, Fischer et al. in a study from Switzerland showed that 60% of intensive care unit (ICU) patients had undergone tracheostomy in the second week (5), while in a study by Kluge et al. from Germany, the corresponding rate was 90% (6). On the other hand, studies from Iran have reported a prevalence rate of 24% (2).
In the past, the first indication for tracheostomy was the upper airway obstruction due to infectious diseases (7).
However, considering the progress in vaccine development and use of antibiotics, infection is not the most prevalent indication for tracheostomy. In most previous studies, avoidance of prolonged intubation is the most common indication for tracheostomy (8,9). However, the results of some studies are still controversial in this area. For instance, the most prevalent indications in some studies were respiratory diseases, head and neck tumors, and trauma to the jaws and skull, respectively (10). In some other studies, the most common indications were reported to be cardiac and pulmonary diseases, neurological disorders, and airway obstructions (7).
Since tracheostomy is an operation in which the upper airway is bypassed, it may pose serious risks to patients.
Also, tracheostomy is one of the most common surgeries in the area of ear, nose, and throat (ENT); therefore, analysis of indications for tracheostomy can be effective in reducing the irreversible complications. The aim of the present study was to analyze the prevalence of tracheostomy indications and to estimate the prevalence of tracheostomy based on the data collected from Iranian studies.

Search strategy and selection criteria
This systematic review and meta-analysis was conducted according to the PRISMA statement (11

Data extraction and risk of bias assessment
Using a standard form, the two authors ("AA" and "AAD") separately extracted the data from the studies,

Statistical analysis
Comprehensive meta-analysis (CMA) software was employed for data analysis. Variance of each study was calculated with regard to binomial distribution, and studies were combined considering the variance and sample size. To calculate the prevalence, 95% confidence interval was used to weigh each of the studies. A random effects model was also applied to combine studies with respect to their heterogeneity.
Moreover, Cochran test and I2 index were utilized to evaluate the heterogeneity of studies.

Funding source
There was no funding source in this study. Two of the authors had the required access to the necessary information. The decision to publish the article was made by all of the authors.  Figure 1.  Table 1.

Frequency of tracheostomy indications
In 24 selected studies, 21 indications were reported.
The results of meta-analysis showed that the most  Table 2. The obtained results were assessed using the random effects model at 95% confidence interval. .10) and the lowest rate found in Ardabil (6.63 in every 100,000 people; 95% CI: 6.41-6.8) (Figure 7).         In another retrospective review, prolonged intubation (35%), upper airway obstruction (28%), neurologic disorders, and craniofacial anomalies (12%) were the most prevalent indications for tracheostomy (34